Blender 2.80 system Req + GPU req
Blender's hardware requirements are documented here. As of now for Blender 2.80 this is:


  Minimum
  
  
  32-bit dual core 2Ghz CPU with SSE2 support
  4 GB RAM
  1280×768 display
  Mouse, trackpad or pen tablet
  Graphics card with 1 GB RAM, OpenGL 3.3
  
  
  Recommended
  
  
  64-bit quad core CPU
  16 GB RAM
  Full HD display
  Three button mouse
  Graphics card with 4 GB RAM
  
  
  Optimal
  
  
  64-bit eight core CPU
  32 GB RAM
  Full HD displays
  Three button mouse and pen tablet
  Graphics card with +12 GB RAM
  
  
  Supported Graphics Cards
  
  These requirements are for basic Blender operation, rendering using
  the GPU requires slightly different requirements. Always make sure to
  install the latest drivers from the graphics card manufacturer
  website.
  
  
  NVIDIA: GeForce 200 and newer, Quadro Tesla architecture and newer, with NVIDIA drivers (list of all GeForce and Quadro GPUs)
  AMD: GCN 1st gen and newer (list of all AMD GPUs)
  Intel: Haswell and newer (list of all Intel GPUs)
  macOS: version 10.12 or newer with supported hardware
  


In order to use the GPU for rendering your hardware needs to fulfill the requirements listed in the documentation. GPU rendering on macOS with AMD graphic cards has been discontinued due to Apple deprecating their OpenCL compiler.

Benchmarking information are available at Blender Open Data.